Passive optical networks are becoming prevalent in part because service providers want to deliver high bandwidth communication capabilities to customers. Passive optical networks are a desirable choice for delivering high-speed communication data because they may not employ active electronic devices, such as amplifiers and repeaters, between a central office and a subscriber termination. The absence of active electronic devices may decrease network complexity and/or cost and may increase network reliability.
FIG. 1 illustrates a network 100 deploying passive fiber optic lines. As shown, the network 100 can include a central office 101 that connects a number of end subscribers 105 (also called end users 105 herein) in a network. The central office 101 can additionally connect to a larger network such as the Internet (not shown) and a public switched telephone network (PSTN). The network 100 can also include fiber distribution hubs (FDHs) 103 having one or more optical splitters (e.g., 1-to-8 splitters, 1-to-16 splitters, or 1-to-32 splitters) that generate a number of individual fibers that may lead to the premises of an end user 105. The various lines of the network 100 can be aerial or housed within underground conduits.
The portion of the network 100 that is closest to central office 101 is generally referred to as the F1 region, where F1 is the “feeder fiber” from the central office 101. The portion of the network 100 closest to the end users 105 can be referred to as an F2 portion of network 100. The network 100 includes a plurality of break-out locations 102 at which branch cables are separated out from the main cable lines. Branch cables are often connected to drop terminals 104 that include connector interfaces for facilitating coupling of the fibers of the branch cables to a plurality of different subscriber locations 105.
Splitters used in an FDH 103 can accept a feeder cable Fl having a number of fibers and may split those incoming fibers into, for example, 216 to 432 individual distribution fibers that may be associated with a like number of end user locations. In typical applications, an optical splitter is provided prepackaged in an optical splitter module housing and provided with a splitter output in pigtails that extend from the module. The splitter output pigtails are typically connectorized with, for example, SC, LC, or LX.5 connectors. The optical splitter module provides protective packaging for the optical splitter components in the housing and thus provides for easy handling for otherwise fragile splitter components. This modular approach allows optical splitter modules to be added incrementally to FDHs 103 as required.
It is common for F1 and F2 cables to be routed underground. When underground construction or other activity is to be undertaken in areas where underground cables are buried, it is necessary to mark the locations of the buried cables before the activity is undertaken. In the case of shielded/armored cables, a field technician can transmit a locator signal (e.g., an RF signal) through the metal shielding of the cables, and then use an above ground sensor (e.g., an RF detector) to detect the signal along the length of the cable and thereby identify the location of the cable. As the cable is detected, the technician can apply a spray paint line to the ground surface so that the location of the underlying cable is identified. By marking the ground surface, the likelihood for the cable to be broken or otherwise damaged during the underground activity is reduced.
In the case of shielded/armored cables, the cables are preferably grounded for safety. In a typical configuration, a grounding plate having grounding pins is provided within the interior of a fiber distribution hub cabinet. The shields of the Fl and F2 cables are electrically connected to the pins of the grounding plate by wires. One of the pins is electrically connected to ground (e.g., a metal rod, post or other member driven into the ground). In this type of hub arrangement, for the field technician to mark the F1 and F2 lines, it is necessary for the field technician to gain access to the interior of the cabinet. Once the cabinet is open, the technician can disconnect the cable of interest from ground and transmit the locator signal through the shielding of the cable. After the location of the cable has been marked, the shield of the cable is reconnected to ground.
Field technicians responsible for marking underground cable are often not employed by the service provider that owns and operates the fiber distribution hub. Furthermore, field technicians responsible for marking cable are typically not trained with respect to the telecommunications equipment typically housed within a fiber distribution hub. Therefore, it can be undesirable for the field technician to have access to the interior of the fiber distribution hub. Moreover, the cabling and other components within a fiber distribution hub can often block access to the grounding plate and/or make the grounding plate difficult to find. Therefore, it is desirable to have a fiber distribution hub having a configuration which allows a field technician to access the grounding plate without having to open the primary cabinet of the fiber distribution hub.